Apulia Platform Research Articles

A NEW REGIONAL PETROLEUM SYSTEMS MODEL FOR CENTRAL ITALY AND THE CENTRAL ADRIATIC SEA SUPPORTED BY BASIN MODELLING AND AN ANALYSIS OF HYDROCARBON OCCURRENCES

The petroleum system in Central Italy and the Adriatic Sea is of great interest for future hydrocarbon exploration. However, major uncertainties remain about key risk elements such as source rock spatial distribution and maturation history, the timing of hydrocarbon migration, and the nature of migration pathways. This paper presents a new regional‐scale petroleum systems model based on an integrated inter‐disciplinary study which includes public‐domain subsurface data on key petroleum systems elements, heat‐flow and petroleum geochemical data, and an extensive set of 1D basin models.Results show the importance of the Mesozoic palaeogeographic and stratigraphic setting which was characterized by the presence of platform and basinal domains. Thermal data highlight an overall higher basal heat flow in platform domains which persist at the present‐day. Considering the geochemical and thermal characteristics of possible source rocks in the study area, the Upper Triassic Burano Formation appears to be the most likely active source rock but only in those geological domains where it has been deeply buried. In particular, source rocks reached maturity only during the most recent Apennine deformation phase in the late Pliocene/early Pleistocene, i.e. after the deposition of regional seals such as the Messinian Gessoso‐Solfifera Formation. Lateral migration is suggested to have occurred to explain most of the known oil accumulations. The margin of the Apulia Platform could have acted as a migration pathway for hydrocarbons, connecting basinal kitchens to the carbonate reservoir units at the top of the platform succession within which oil and gas accumulations have been proven. Heavy oils could represent early expulsion products from the source rock, but may also locally be a result of biodegradation due to recent partial exhumation of the traps and the loss of lighter components.The results of this study may support ongoing and future exploration efforts over other carbonate platforms in the study area, and more widely on carbonate targets elsewhere in the Mediterranean region.

Reappraisal of some species of the giant galericine Deinogalerix (Mammalia, Eulipotyphla, Erinaceomorpha, Erinaceidae) from the Miocene of south-eastern Italy, with a review of the genus

A revision of the remains of Deinogalerix from the Terre Rosse of Gargano, stored at the Department of Earth Sciences of Florence, improved our knowledge of the genus. The goals of this study are to clear the taxonomic status of the specimens and to tackle several issues connected with the evolutionary relationships of the different species. The sample of dental remains of Deinogalerix freudenthali provides new information, which confirms that this species belongs to the most primitive members of the genus, alongside D. masinii. It is now clear that D. freudenthali is very close to the hypothetical ancestor of all other Gargano species, except D. masinii. Nonetheless, the oldest fissures of the Gargano Terre Rosse contain also primitive species of unsettled taxonomic and phylogenetic position. The present analysis shows the systematic validity of D. minor and D. intermedius, whose status was debated. Moreover, the study verifies the consistency of the two phyletic lineages Deinogalerix minor–D. brevirostris and Deinogalerix intermedius–D. koenigswaldi, as well as the co-occurrence of members of the two lines at least in the most recent Terre Rosse fissures. The enhanced information contributes to our understanding of the genus Deinogalerix and especially of the most ancient phases of colonisation of the Apulia Platform. Nonetheless, the fossil record of the genus remains imperfect, with many gaps blurring the origins of its various evolutionary lines.

Internal waves as controlling factor in the development of stromatoporoid-rich facies of the Apulia Platform margin (Upper Jurassic-Lower Cretaceous, Gargano Promontory, Italy)

During the Late Jurassic, stromatoporoid-rich buildups were developed in south and intra-Tethys realms. These stromatoporoid buildups are mainly characterized by the high percentage of intraclastic-bioclastic debris, as main components of buildup bodies. However, the source of hydrodynamic energy resulted in debris production, is still a matter of debate. This study examines the Upper Jurassic-Lower Cretaceous stromatoporoid-rich buildups of Monte Sacro Limestones (MSL), Apulia Carbonate Platform (ACP), in order to describe the main carbonate facies along the study area, as well as the possible source of turbulence. Three main lithofacies have been distinguished: LF1 — stromatoporoid-rich facies with two subfacies (LF1-S1: floatstone with wackestone to fine-grained packstone, LF1-S2: rudstone-floatstone with intraclastic-bioclastic packstone-grainstone), LF2 — stromatoporoid-coral facies distributed in wackestone to packstone matrix (LF2-S1) and tabular stromatoporoid-corals surrounded by wackestone matrix (LF2-S2) and, LF3 — stromatoporoid-microbial facies. These facies were deposited along the mid part of a distally steepened ramp. The in-situ form of stromatoporoids was developed in a mud-dominated matrix (LF1-S1) under low-energy conditions while the intraclastic-bioclastic rich facies (LF1-S2) were deposited under a high-energy condition. The distribution of LF2 and LF3 in muddy matrix suggests occurrence of these lithofacies in quiet environments.The biotas were influenced by several factors including nutrient and light availability as well as by hydrodynamism. The stromatoporoid-rich buildups in ACP can be categorized as phototrophic-heterotrophic reefs generated in a pure carbonate environment. The light penetration was confined, resulted in the high development of light-independent micro-encrusters (Tubiphytes morronensis), in a mesophotic condition, where the environment was not ideal for light-dependent microencrusters (Lithocodium-Bacinella) to grow.We suggest that debris-dominated stromatoporoid-rich lithofacies (LF1) thrived in meso-oligophotic setting, along the nutricline and were affected by more than episodic high-energy events in a context where the surface waves were not effective. In such environments, internal waves can be an effective candidate to explain the episodic turbulences to produce the debris-rich facies of LF1-S2. Moreover, internal waves can pump the nutrient-rich waters to the buildups, and create an ideal setting where these metazoan communities thrived.

Mass Transport Deposits and geo-hazard assessment in the Bradano Foredeep (Southern Apennines, Ionian Sea)

Seafloor bathymetry, combined with multi-scale seismic reflection profiles, were used to describe the morphostructural setting of the Bradano Foredeep (Gulf of Taranto, northern Ionian Sea), where a submerged portion of the Southern Apennines is facing the Apulia Platform in the Calabrian Arc convergent margin. In this complex area, marine geophysical data highlight the presence of two mega-slide deposits at the shelf-slope transition, which are most likely the largest ever described in the region. These slid masses, named the Bradano Basento MegaSlide (BBMS) and Bradano Basento MegaSlide 1 (BBMS1), form a Mass Transport Deposit Complex (MTDC) affecting and eroding the topmost portion of the outer Apennines deformation front and the Apulian Foreland Ramp. It was emplaced in late Pleistocene times inside the narrow (about 10 km wide) Bradano Foredeep basin, a Plio-Pleistocene submarine trough developing at the chain front. The youngest of these deposits (BBMS1) likely predates the Last Glacial Maximum. Location of the MTDC within the subduction complex suggests that active tectonics and seismic shaking might represent the main triggering mechanisms for gravitative instability in this area, although gravitational tectonics and sediment creeping mechanisms cannot be excluded. On the other hand, size and distribution of the MTDC in the sedimentary record of the Bradano Foredeep suggest the need of re-evaluating the potential for large earthquakes/tsunamis, and more in general geological hazard related to submarine sliding masses, along the coast of this highly populated area.

1:5,000 geological map of the upper Cretaceous intraplatform-basin succession in the "Gravina di Matera" canyon (Apulia Carbonate Platform, Basilicata, southern Italy)

Along the slopes of the Gravina di Matera canyon, below and in front of the Sassi di Matera, i.e., the old Matera town (Basilicata, southern Italy), an about 200 m thick succession of upper Cretaceous carbonates extensively crops out. These carbonates belong to the Apulia Carbonate Platform and, in the official geological map, are referred to the Calcare di Altamura Fm, a lithostratigraphic unit composed of shallow-marine peritidal limestones. In order to study the whole outcropping succession, a geological survey was performed in the area and an unaspected intraplatform shallow-basin suite of limestones has been recognized within the Calcare di Altamura Fm. On the basis of lithologic characters, the whole succession has been divided into informal lithostratigraphic units a-g. The base of the succession (unit a) is represented by a crudely stratified bioclastic floatstone-rudstone locally interested by in situ brecciation, a phenomenon that often is the precursor of deep changes in a carbonate platform. Unit a sharply passes upward to thinly bedded and finely planar-laminated mudstone interested by slumps (unit b), conformably covered by dolostones (unit c). Dolostone gradually passes to cherty limestones (unit d) that in turn pass to wackestones (unit e) covered by a megabreccia (unit f). All these units (a-f) indicate that this area of the Apulia Platform performed a change from classic platform environments to slope- and to basin-ones, before the restarting of typical facies of shallow-marine carbonate platform environments (unit g). This subdivision in units of the outcropping succession led us to informally define a member, the Matera member (ALT1), within the upper Cretaceous Calcare di Altamura Fm (ALT). Most likely, the Matera member (units a-f) represents a shallow-basin developed within the Apulia Platform during Late Cretaceous, most likely related to extensional tectonics. Other examples of slope-to-basin sedimentary suite were previously observed within the upper Cretaceous succession of the Apulia Platform and the occurrence of another shallow-basin in the interior of the same platform opens a new and still understimated regional tectonic- and paleogeographic-scenario. Moreover, it should be highlighted that the geological surveyed area belongs to a Regional Natural Park since the 1990 (Parco Archeologico Storico Naturale delle Chiese Rupestri del Materano also known as Parco della Murgia Materana) and that Matera, besides being in the Unesco Word Heritage list since the 1993, has been voted European Capital of Culture 2019. Therefore, the obtained 1:5,000 geological map, apart from documenting some lithostratigraphic evidences of the intraplatform basin, represents an essential tool for both (i) future studies regarding the upper Cretaceous tectono-stratigraphic evolution of the Apulia Platform, and (ii) a geological base for many visitors interested in the cultural and geological heritage of Matera and its territory.

Observations on the postcranial anatomy of Hoplitomeryx (Mammalia, Ruminantia, Hoplitomerycidae) from the Miocene of the Apulia Platform (Italy)

Observations on the postcranial anatomy of Hoplitomeryx (Mammalia, Ruminantia, Hoplitomerycidae) from the Miocene of the Apulia Platform (Italy)

Magnetotelluric investigation in the High Agri Valley (southern Apennine, Italy)

Abstract. In this paper we present the result of a magnetotelluric (MT) investigation carried out across the High Agri Valley (HAV), southern Italy. Several MT soundings were carried out in order to obtain a ~15 km long 2-D resistivity model with an investigation depth of ~10 km. The main aim was to provide valuable data on the geological and structural setting of the HAV. The MT model was compared with pre-existing geological, geophysical and seismic data. The MT model can be schematized as a superposition of three stack lateral varying layers with different thickness and resistivity values: a surficial low–medium resistivity layer associated with the Quaternary deposits and to the allochthonous units; and a deeper high resistivity layer related to the Apulia Platform, separated by a thin layer connected to the mélange zone and to the Pliocene terrigenous marine deposits. Sharp lateral resistivity variations are interpreted as faults that, on the basis of accurate focal mechanism computations, display normal-faulting kinematics.

Scontrone (central Italy), signs of a 9-million-year-old tragedy

The fossilierous bonebeds of Scontrone (Abruzzo region, central Italy) are preserved in tidal-flat aeolian calcarenites at the base of the Lithothamnion Limestone, a Miocene carbonate ramp widespread in the central-southern Apennines. The site bears evidence of a catastrophic event at 9 Ma. Reported are the results of the palaeobiological and taphonomic analysis conducted on the rich vertebrate assemblage, particularly on the remains of Hoplitomeryx (Mammalia, Artiodactyla, Ruminantia), recovered from the so-called Scontrone calcarenites between 1992 and 2012. This is the first taphonomic study of a Late Miocene continental bone assemblage preserved in coastal deposits. The bones are not in primary context. They were likely exhumed during the initial phase of a marine transgression after a period of primary ‘storage’ within a possibly flood-generated deposit in an estuarine environment. The mortality patterns indicate that the carcasses accumulated in a short time (within a year). The bones of the disarticulated skeletons were then removed, broken in a dry and brittle state, scattered over wide carbonate ramps along an arid to semi-arid, wind-exposed coastline and eventually buried again in aeolian calcarenites that drape transgressive tidal-flat creek deposits. The analysis also reveals that hoplitomerycids were possibly seasonal reproducers and that the land they inhabited, the so-called Apulia Platform, was probably swept by sudden, disastrous, storm-supplied flash floods.

The Miocene vertebrate-bearing deposits of Scontrone (Abruzzo, Central Italy): Stratigraphic and paleoenvironmental analysis

The Miocene carbonate deposits of Scontrone (Abruzzo, Central Italy) are well known among palaeontologists because of their fossil vertebrate content that exhibits striking similarities to those of the remarkable “Terre Rosse” faunal complex of the Gargano region, defining the existence of the Miocene Central Mediterranean Apulia paleobioprovince. The main goal of this paper is to establish the age and environment of the Scontrone vertebrate bonebeds. The vertebrate remains are embedded in the basal portion of the Lithothamnion Limestone, a widespread carbonate-ramp lithosome representative of the Tortonian-early Messinian transgression over the entire Apulia Platform. The bonebeds belong to marginal-marine deposits (here called “Scontrone calcarenites”) preserved in a small area below transgressive ravinement surfaces. The rapid vertical and lateral facies variations displayed by the “Scontrone calcarenites”, together with paleoenvironmental considerations deriving from the vertebrate association, document a complex wave-dominated river-mouth depositional setting developed over a large, flat and semi-arid carbonate ramp. The “Scontrone calcarenites” have been split herein into five facies associations representing the stratigraphic response to a discontinuous or punctuated transgression within an overall rise of the relative sea level. Because of the absence of age-diagnostic fossils, the age of the “Scontrone calcarenites” cannot be directly defined through their paleontological content. However, a regional stratigraphic correlation between the Lithothamnion Limestone of Scontrone and the Lithothamnion Limestone of northern Majella, which is biostratigraphically well constrained, allows the attribution of the “Scontrone calcarenites” to the Tortonian.

The Ombrina-Rospo Plateau (Apulian Platform): Evolution of a Carbonate Platform and its Margins during the Jurassic and Cretaceous

In this paper we analyze the Jurassic and Cretaceous evolution of the buried northwards stretch of the Apulia Platform (Southern Italy) (Ombrina-Rospo Plateau – ORP), and adjacent Adriatic Basin. Exploration wells indicate that inner platform carbonate facies across the ORP in the Jurassic and Lower Cretaceous are capped, along a subaerial exposure surface, by Oligocene/Miocene carbonates. A NW-trending intra-platform basin (“Casalbordino Corridor”) was infilled with shallow- to deeper-water sediments in the late Early to Late Cretaceous interval, while platform margins were experiencing tectonic reactivation.The ORP-to-basin transitional belt formed a corner, defining a NW and a NE margin. The NW margin was essentially stationary. A syn- and early post-rift platform-toe bypass wedge formed when late Hettangian–Sinemurian extension produced the platform/basin relief. Export of platform material, coupled with a halt of faulting, made the platform/slope profile continuous in the late Early or early Middle Jurassic (possibly across an ooidal rim). Late Jurassic Ellipsactinia/coral reefs passed downdip into bioclastics. The Maiolica Fm. displays two cycles (M1, M2), where M2 onlaps the slope built by M1. In the Aptian, with lithospheric arching, a high angle fault rejuvenated the margin. Off this margin, a narrow basin, locked between the ORP and a pelagic carbonate platform, was largely infilled with turbidites sourced by the ORP, but the high hampered the dispersal of the sand fraction. The NE margin displays prograding ooidal to bioclastic clinoforms (Middle and Upper Jurassic) downlapping onto the rift basin. In the Lower Cretaceous, the platform recovered after a slow-down of carbonate productivity (M1/2 boundary). The Marne a Fucoidi Fm. thickens at the toe of, and seals, a fault backstepping the margin. Further backstepping occurred ∼5 km platformwards along a (Cenomanian?) normal fault, producing room for a rudist factory. A retreating rocky shoreline sourced breccias, while downdip the shallow water facies graded into the Scaglia Fm. basin along a ramp-like profile with low angle clinoforms, merging with turbidites.

Mechanical stratigraphy and (palaeo-) karstification of the Murge area (Apulia, southern Italy)

Abstract The Cretaceous Apulia Platform, exposed in the Murge area (southern Italy), suffered intense (palaeo)karstification. This study focuses on the controlling factors of karstification with emphasis on fracturing. Mechanical stratigraphy was used to calculate the fracture density within different sedimentary sequences. Several mechanical units were defined and a characteristic relationship was found between unit thicknesses and fracture density, that is, fracture density increases if layer thickness decreases. In some of the quarries studied, sedimentary cycles are clearly present that are also reflected in the fracture density logs. The degree of karstification within a mechanical unit is proportional to the mean fracture spacing. Based on fracture orientation data extracted from LIDAR scans, different orientation clusters were observed between fractures that are karstified and fractures that are not karstified, post-dating karstification. The clusters of karstified fractures are related to the compression of the southern Apennines. The fractures became dissolution enlarged during the Pleistocene uplift caused by bulging of the Apulia Platform. This main karstification phase occurred prior to Late-Pleistocene deposition and before the formation of orthogonal fracture sets.

A bridge too far. Comment on “Processes of island colonization by Oligo-Miocene land mammals in the central Mediterranean: New data from Scontrone (Abruzzo, Central Italy) and Gargano (Apulia, Southern Italy)” by P.P.A. Mazza and M. Rustioni [Palaeogeography, Palaeoclimatology, Palaeoecology 267 (2008) 208–215

Mazza and Rustioni [Mazza, P.P.A., Rustioni, M., 2008. Processes of island colonization by Oligo-Miocene land mammals in the central Mediterranean: New data from Scontrone (Abruzzo, Central Italy) and Gargano (Apulia, Southern Italy). Palaeogeogr. Palaeoclim. Palaeoecol. 267 (3–4), 208–215.] suggest that land bridges played an important role in the colonization of the Abruzzo–Apulian bioprovince, as shown by the fossil vertebrates from Scontrone and Gargano. Would they have been able to demonstrate that land bridges indeed played a role in the dispersion of mammals, this would have implied that we had to rethink the modes of colonization for many other isles and rewrite our theories on island biogeography. Unfortunately, their evidence falls short, and even though their paper provides new insights in the history of the insular faunas of the Apulia platform, there is no reason to assume that land bridges played any role in the colonization of these islands.

Surface kinematics in the Alpine–Carpathian–Dinaric and Balkan region inferred from a new multi-network GPS combination solution

The understanding of the intraplate tectonics of Central Europe requires a detailed picture of how stress is transferred from the interaction of the Eurasian, Nubian and Anatolian plates to the Alpine, Carpathian, Pannonian and Dinaric regions. Recent strain distribution is controlled by the Adria horizontal push, by the Vrancea vertical slab pull and associated horizontal displacements, and by the Aegean/Anatolia extension and slab-roll back. We present a horizontal velocity field for the Alpine-Carpathian-Pannonic-Dinaric and Balkan regions resulting from a new combination of seven different GPS networks formed from permanent and campaign stations. Dedicated velocity profiles in two specific regions are studied in detail. One is the Alpine Pannonian region, with a detailed picture of the NS indentation of the Adria microplate into the Southern Alps, in NE Italy, the deformation in the Tauern Window and the eastwards kinematics of a Pannonian plate fragment. The second study region includes Transylvania, the Southern Carpathians up to the Aegean sea and Albania, where a major right lateral shear deformation exists as a consequence of the NE convergence of the Apulia platform towards the Dinarids, and the SSW motion of Macedonia, Western Bulgaria and Rumania, related to the Hellenic arc dynamics in the Eastern Mediterranean. The profiles in the Alpine–Pannonian area indicate that a velocity drop of 2.5 +/− 0.4 mm/yr associated with the Adria indentation concentrates on a segment of some 50 km south of the Periadriatic fault. The deformation becomes extensional by a similar amount just north of the Periadriatic fault, in the Tauern Window, where the updoming of the Tauern Window implies vertical motion which could well be associated with surface extension. In the EW profile, we observe a sudden velocity change of 1.5 +/− 0.2 mm/yr in 20 km, corresponding to the right lateral Lavant fault, which seems to mark the border between dominant indentation kinematics to the West and dominant extrusion kinematics to the East. Three profiles are considered in Southern and Eastern Europe: one across the lower Adriatic sea from Apulia in Italy to the southern Dinarides, which enables it to constrain the velocity drop associated with the subduction of the Adria microplate into the Dinarides to 3.2 +/− 0.5 mm/yr in 140 km. The second profile is longitudinal and constrains the velocity inversion of 7.4 +/− 1.0 mm/yr in 350 km associated with right lateral shear faults in Albania. The third profile crosses the Transylvania region with a shortening of 2.3 +/− 1.0 mm/yr in 220 km, and the Wallachian–Moesian region up to the Chalcidic peninsula in N Greece. This lower part of the profile implies an extensional stretch of the upper crust of 3.2 +/− 0.9 mm/yr in 440 km, culminating in the Hellenic arc. Strain rate maps are presented in this regional scale, showing the excellent agreement between fault plane solutions of crustal earthquakes and the eigenvectors of the GPS derived two dimensional strain rate tensor. Three profiles are considered in the Balkan and SE Carpathians: one across the lower Adriatic sea from Apulia in Italy to the southern Dinarides, which enables to constrain the velocity drop associated to the subduction of the Adria microplate into the Dinarides to 3.2 +/− 0.5 mm/yr in 140 km. The second profile is longitudinal and constrains the velocity inversion of 7.4 +/− 1.0 mm/yr in 350 km associated to right lateral shear faults in Macedonia, a highly seismic region. The third profile crosses the Transylvania with a shortening2.3 +/− 1.0 mm/yr in 220 km, and the Wallachian–Moesian region up to the Chalcidic peninsula in N Greece. This lower part of the profile implies an extensional stretch of the upper crust of 3.2 +/− 0.9 mm/yr in 440 km, culminating in the Hellenic arc.

Evoluzione cretacica di un settore della piattaforma apulada dati di sottosuolo e di affioramento (Appennino campano-molisano)

Seismic and outcrop data suggest that the Mesozoic carbonate successions cropping out in the Matese and Camposauro Groups, in the central-southern Apennines of peninsular Italy, can be interpreted as an exposed part of the Inner Apulia Platform (PAI). Cretaceous sequences have been studied in detail in the field and compared with the coeval carbonate sediments of the Inner Apulia Unit cored in the Benevento oilfield and in the Monte Taburno 1 and Morcone 1bis wells. Subsurface data show that, starting from the late Aptian time onwards, the Inner Apulia Platform was dismembered into a series of sub-domains which included shelfal productive areas and a series of small intra-platform basins (or elongated depressions). These basins have a mean Apennine orientation and were locally affected by significant subsidence. Outcrop analyses indicate similar tectono-sedimentary trends and led to the recognition of three main structuring phases, that can be ascribed Middle Aptian, Late Aptian-Albian and Early-Middle Cenomanian time intervals, respectively. The main structural features, formed during the first structuring phase, were repeatedly reactivated during the subsequent phases and controlled the palaeo-environmental evolution of the various sub-domains, that were characterised by different facies and facies associations. The facies analysis from integrated outcrop and core data shows analogous evolutionary trends. In particular, starting from the middle-late Aptian, the carbonate factories display a sharp variation in the sedimentary dynamics and depositional architectures: the uniform pre-Aptian shallow-lagoon rimmed system rapidly evolved into a much complex system in which shallow-water rudist-dominated carbonate factories were located alongside by-pass and deeper basinal areas. At outcrop, the steering toward open marine conditions can be correlated with the early (middle Aptian) structuring phase of the platform. This trend is marked in the easternmost studied areas by the formation of tectonically active margins, characterised by the presence of complex channel networks, but is also evident in the innermost sectors (western areas) of the shelves, by the increase in frequency and intensity of high-energy events. The varied time-span of the «mid-Cretaceous» stratigraphic gaps (see Carannante et alii , 1987, 1994; Ruberti, 1992) supports the hypothesis of a complex tectonically-controlled palaeo-topography and of a differential evolution of the related sub-domains. Since the late Turonian, a shallow sea encroached on the exposed lands. Deposition of shallow water rudist-rich sediments followed. The peculiar features of the benthic assemblages which dwelled patchily in loose substrata resulted in the lack of real reefs at the shelf margins. This enhanced the water circulation and controlled the 3D arrangement of the sedimentary bodies made up mainly of large coalescing sheets of winnowed fine to coarse skeletal sands. The skeletal fraction, produced by intensive bio-erosive and mechanical processes acting on mainly diagenetically stable calcite-shelled organisms, covered most of the open shelf. This large amount of loose silt- to pebble-sized bio-clastic debris was periodically removed from the shelf, transported (often through submarine channels) and re-sedimented in the adjacent strongly subsiding intra-platform basins formed during the Lower Cretaceous and Cenomanian structuring phases. Finally, the study of available seismic lines allowed for correlation between the Matese Mountains and the Morcone 1 well and the Benevento oilfield. These lines, tied to well data, show a complex structure formed by several thrusts where older units pertaining to the Apulia Platform are piled up over younger siliciclastic units of the Miocene Foredeep. Further, the foredeep siliciclastic deposits are as old as lower-middle Tortonian in the Eastern Matese, while as young as late Tortonian in the Morcone 1 well and Pliocene in the Benevento oilfield. This remarkable time-polarity appears to support the hypothesis presented in this contribution, and makes it possible to constrain the timing of the thrust emplacement for this sector of the Apennine Chain.

Structural architecture of the central Apennines: Interpretation of the CROP 11 seismic profile from the Adriatic coast to the orographic divide

We present an interpretation of the eastern half portion of the CROP 11 line, a deep reflection seismic profile 265 km long that cuts across the central Apennines from the Tyrrhenian coast to the Adriatic coast. In the study area the line cuts across a pile of thrust sheets that underwent tectonic transport between the Messinian and the Pleistocene. In its easternmost part, the line runs through the Plio‐Pleistocene deposits of the Adriatic foredeep. In the foreland region the CROP 11 line integrates previous information on the crustal structure derived from petroleum exploration and from deep seismic sounding refraction experiments. In particular, the CROP 11 line confirms the existence of a very thick sedimentary sequence underlying the Mesozoic‐Tertiary carbonates of the Apulia Platform interpreted as the Paleozoic‐Triassic sedimentary cover of a pre‐Cambrian crystalline basement. In the mountain chain, where the base thrust of the orogenic wedge reaches a depth of about 25 km, this sedimentary sequence appears to be the deepest geological unit incorporated in the thrust system. This interpretation of the CROP 11 profile suggests an unusual thin‐skin tectonic style implying the detachment from the original basement and the incorporation in the post‐Tortonian tectonic wedge of a very thick Paleozoic‐Triassic sedimentary sequence possibly affected by low‐grade metamorphism in the lower part. Other new suggestions from the CROP 11 seismic data concern the origin of the Fucino basin, one of the most remarkable Plio‐Pleistocene intramontane basins. The normal faults bordering this structural depression, as other important normal faults present in the central Apennines (e.g., the Caramanico fault system in the Majella region), seem to have been controlled by gravitational‐collapse processes driven by uplift during crustal shortening rather than by a generalized extension subsequent to the Apennine compression, as usually reported in the geological literature. If this interpretation is correct, the strong seismic activity in correspondence to the Apennine watershed may be related to the very recent increase in the structural relief caused by an out‐of‐sequence propagation of the active thrusts.

Structural setting of the Southern Apennine fold-and-thrust belt (Italy) at hypocentral depth: The Calore Valley case history

Abstract The reconstruction of the main structural features of the Southern Apennines (Italy), in correspondence with the focal volume of some strong earthquakes that have affected this chain, can be attempted by analysing reflection seismic lines and deep well logs in comparison with surface geology. For instance, the Calore Valley and its surroundings have been the object of intense hydrocarbon exploration, and a wealth of subsurface data is available. Moreover, this area was affected by the 1688 Sannio earthquake (macroseismic magnitude 7.1), and a new location has recently been proposed for the related causative fault system. The present work defines the structural setting of the Southern Apennine chain in correspondence with this new location, and compares it with similar cases along the Italian peninsula. The analysis was focussed on the reconstruction of deep tectonic units (formed by the buried Apulia carbonate platform succession), which generally correspond to the hypocentral depths of strong earthquakes along the axis of the Southern Apennines. The results show that the Apulia platform succession is affected by three main thrusts, locally accompanied by backthrusts. The top of this succession is relatively shallow: the maximum depth does not exceed 1.8 s TWT (i.e. about 3500 m b.s.l.), while minimum depths occur in correspondence with the ramp anticlines culminations, at ∼0.5 s TWT (i.e. at about 500 m b.s.l.). Moreover, data suggest that the underlying Paleozoic basement is possibly involved in thrusting. In a regional perspective, extensional seismogenic structures along the axis of the Southern Apennines seem to share some common characteristics. Indeed, they develop (i) in correspondence with an uplifted Paleozoic basement; (ii) at the rear of a set of thrusts that account for the shallow Apulia units; (iii) at the surface, in proximity to the leading edge of a surficial tectonic unit formed by the Apennine carbonate platform succession. The 1688 seismogenic fault system fits in with these common traits. In the light of this, we finally speculate that these common characteristics in the architecture of the chain could provide a key to the location of the major seismicity along the axis of the Southern Apennines and an interpretative model for the identification of possible areas of seismic gap in this part of the Italian peninsula.

The regional record of Albian oceanic anoxic events at the Apulian Platform Margin (Gargano Promontory, southern Italy)

The Gargano Promontory, located on the eastern margin of the Apulia Platform, represents a distinctive Tethyan area where the transition from carbonate platform to adjacent basin is exposed on land. The Albian stratigraphic record, represented by shallow-water, slope and deep-water deposits, provides a good opportunity to investigate the regional response to oceanic anoxic events (OAEs) in different depositional settings by using an integrated, high-resolution micropalaeontological (planktonic foraminifers and calcareous nannofossils) approach. Results show that organic matter preservation is confined to the more distal areas (Marne a Fucoidi Formation), and consists of black shale intervals from the middle and late Albian ( Ticinella primula/Prediscosphaera columnata Zones; upper Ticinella praeticinensis Subzone/ R. achlyostaurion Zone, respectively). Integrated biostratigraphic data correlate the intervals of black shale deposition to the Urbino and Amadeus levels, previously identified and named in the Umbria-Marche Basin. These black shales record the effects of OAEs 1b and 1c. The biotic changes in the pelagic Albian succession of the Apulian Platform Margin provide evidence for episodes of eutrophication that correlate to the deposition of these black shales. Genetic models for the two episodes of organic matter preservation are proposed, taking into account both global and local controlling factors.

Regional record of a global oceanic anoxic event: OAE1a on the Apulia Platform margin, Gargano Promontory, southern Italy

The Gargano Promontory of southern Italy, located on the eastern margin of the Apulia Platform, represents a peculiar Tethyan area where the transition between carbonate platform and adjacent basins is exposed on land. The Aptian stratigraphic record, represented in shallow-water, slope and deep-water deposits, provides a good opportunity to investigate the regional response to the worldwide documented climatic, biotic and palaeoceanographic changes related to Oceanic Anoxic Event 1a (OAE1a). A synthesis of data previously published (Ischitella and Coppitella sections), together with original data (Val Carbonara and Coppa della Guardia sections), from four stratigraphic sections from different depositional settings (proximal to distal) is provided, using an integrated, high-resolution micropalaeontological (planktonic foraminifera and calcareous nannofossils) and, for one section, geochemical (stable carbon and oxygen isotopes) approach. Organic matter preservation is confined to the more distal areas and consists of two thin intervals of black shales in the Aptian portion of the Marne a Fucoidi Formation. Biostratigraphic data assign the older black shale (5 cm thick) to the Selli Level equivalent (OAE1a, Lower Aptian); this carbon-rich interval is immediately followed by another black shale (7–10 cm thick) of early Late Aptian age. OAE1a is generally interpreted as a high-productivity event during a warming interval, followed by a cooling trend. In the Gargano Promontory, although the oxygen isotope curve indicates the above-mentioned climatic evolution, the micropalaeontological data do not support high fertility of the surface water, whereas micropalaeontological and geochemical data for the younger black shale do record high productivity (radiolarian increase in overall abundance, low nannofossil and foraminiferal species richness, increase in abudance of nannofossil fertility indices) associated with a cooling trend. The carbon and oxygen isotope record is in line with evidence from the curves documented elsewhere, whereas, among the biotic events, only the “nannoconid crisis” preceding OAE1a is revealed to be globally correlable. Environmental models for the two episodes of organic matter preservation are proposed, taking into account both global and local controlling factors.

Biotic changes and their control on Oligocene-Miocene reefs: A case study from the Apulia Platform margin (southern Italy)

The Oligocene-Miocene represents, for the Cenozoic, a period of extensive reef development and is characterized by a number of important changes influencing both carbonate-producing biota and architecture of reefs and carbonate platforms. The Mediterranean region, in particular, was characterized during this time by a complex palaeogeographic and climatic history with stepwise transition towards cooler conditions, biotic turnovers and the complete disappearance of zooxanthellate corals and reefs at the very end of the Miocene. A comparative study of two reef complexes that in different times (Chattian and Messinian) grew in the same physiographic and depositional setting, i.e. the stable, undeformed eastern margin of the Apulia Platform (eastern coast of the Salento Peninsula, southern Italy), highlights evolutionary, ecological and climatic changes that differentiate Oligocene and Late Miocene reef biota of the region. In particular, the study illustrates how different reef biotic assemblages can produce different reef types, frameworks and growth fabrics along reef tracts and reef slopes. The Chattian reef is characterized by a homogeneous reef-building biota, being largely dominated by a high diversity and abundant coral fauna associated with a moderate presence of coralline algae, and thus forming a single reef type. In contrast, the Messinian reef shows a very low coral diversity but several other reef-building components with abundant and varied secondary reef builders (coralline algae, Halimeda, encrusting foraminifera, bryozoans, serpulids and microbial associations). The reef, therefore, is characterized by a heterogeneous reef-building biota that forms different frameworks and growth fabrics. The feedback to the environment of this different biotic composition is very evident in the two reefs and especially in the slope. During the Chattian a slope, mainly consisting of gravity-displaced debris, resulted from the abundant production of reef rubble, associated with a relatively poor framebuilding capacity. Conversely, during the Messinian, a biologically stabilized slope resulted from proliferation of a variety of binding organisms that strongly colonized the substrate. The climatic cooling which occurred during the Miocene may be considered the main controlling factor of the diversity turnovers and changes that affected the coral fauna, but other environmental factors, such as changes in nutrient regimes and in hydrodynamic conditions of the sea associated with the emerging Apennine chain, may have played a role in determining differences in the reef biota and in the reef facies.

Jurassic Dinosaur Footprints from Southern Italy: Footprints as Indicators of Constraints in Paleogeographic Interpretation

Three loose blocks, rich in dinosaur footprints, were found in a small pier at Mattinata (Gargano Promontory, Foggia, Italy), most probably quarried from the Upper Jurassic Sannicandro Formation. All of the footprints in the blocks are ascribed to medium-sized theropod trackmakers. Recent track discoveries from both the Early Cretaceous San Giovanni Rotondo Limestone and the Late Cretaceous Altamura Limestone, as well as this new discovery, reveal the consistency of terrestrial associations along the southern margin of the Tethys Ocean in the peri-Mediterranean area at the end of Jurassic through Cretaceous times. The presence of these dinosaur-track-rich levels within marine sediments of the Apulia Platform underlines the relevance of dinosaur footprints as a means of constraining paleogeographic reconstructions.